Competition may play an important role during the evolution of new species, but empirical evidence for this is scarce, despite being implicit in Charles Darwin's work and support from theoretical studies.
Dr Martin Genner from Bristol's School of Biological Sciences and colleagues used population genetics and experimental evidence to demonstrate a role for competition that leads to the differentiation of new species within the highly diverse cichlid fishes of Lake Tanganyika in East Africa.
They found that the cichlid fish Telmatochromis temporalis shows two genetically distinct ecomorphs (local varieties of a species whose appearance is determined by its ecological environment), that strongly differ in body size and the habitat in which they live.
Dr Genner said: "We found large-sized individuals living along the rocky shoreline of Lake Tanganyika and, in the vicinity of these shores, we found small-sized individuals, roughly half the size of the large ones, that live and breed in accumulations of empty snail shells found on sand."
According to the study, the bigger fish outcompete the smaller ones, driving them away from the preferred rocky habitats and into the neighbouring sand, where the smaller fish find shelter for themselves and their eggs in empty snail shells.
"In effect, big and small fish use different habitats; and because of this habitat segregation, fish usually mate with individuals of similar size. There is virtually no genetic exchange between the large- and small-bodied ectomorphs," Dr Genner commented.
Speciation occurs when genetic differences between groups of individuals accumulate over time. In the case of Telmatochromis there are no obvious obstacles to the movement and interaction of individuals. But, the non-random mating between large- and small-bodied fish sets the stage for the evolutionary play.
Dr Genner said: "The relevance of our work is that it provides experimental evidence that competition for space drives differential mating in cichlid fish and, in time, leads to the formation of new species. Nature has its ways – from body size differences to the formation of new species. And clearly, size does matters for Telmatochromis and for fish diversity."
The study was carried out by evolutionary biologists from the University of Bristol, the Natural History Museum London, the University of Kyoto and the Natural History Museum in Bern.
'Competition-driven speciation in cichlid fish' by Kai Winkelmann, Martin J. Genner, Tetsumi Takahashi and Lukas Rüber in Nature Communications
Hannah Johnson | EurekAlert!
The importance of biodiversity in forests could increase due to climate change
17.11.2017 | Deutsches Zentrum für integrative Biodiversitätsforschung (iDiv) Halle-Jena-Leipzig
Win-win strategies for climate and food security
02.10.2017 | International Institute for Applied Systems Analysis (IIASA)
Heat from the friction of rocks caused by tidal forces could be the “engine” for the hydrothermal activity on Saturn's moon Enceladus. This presupposes that...
The WHO reports an estimated 429,000 malaria deaths each year. The disease mostly affects tropical and subtropical regions and in particular the African continent. The Fraunhofer Institute for Silicate Research ISC teamed up with the Fraunhofer Institute for Molecular Biology and Applied Ecology IME and the Institute of Tropical Medicine at the University of Tübingen for a new test method to detect malaria parasites in blood. The idea of the research project “NanoFRET” is to develop a highly sensitive and reliable rapid diagnostic test so that patient treatment can begin as early as possible.
Malaria is caused by parasites transmitted by mosquito bite. The most dangerous form of malaria is malaria tropica. Left untreated, it is fatal in most cases....
The formation of stars in distant galaxies is still largely unexplored. For the first time, astron-omers at the University of Geneva have now been able to closely observe a star system six billion light-years away. In doing so, they are confirming earlier simulations made by the University of Zurich. One special effect is made possible by the multiple reflections of images that run through the cosmos like a snake.
Today, astronomers have a pretty accurate idea of how stars were formed in the recent cosmic past. But do these laws also apply to older galaxies? For around a...
Just because someone is smart and well-motivated doesn't mean he or she can learn the visual skills needed to excel at tasks like matching fingerprints, interpreting medical X-rays, keeping track of aircraft on radar displays or forensic face matching.
That is the implication of a new study which shows for the first time that there is a broad range of differences in people's visual ability and that these...
Computer Tomography (CT) is a standard procedure in hospitals, but so far, the technology has not been suitable for imaging extremely small objects. In PNAS, a team from the Technical University of Munich (TUM) describes a Nano-CT device that creates three-dimensional x-ray images at resolutions up to 100 nanometers. The first test application: Together with colleagues from the University of Kassel and Helmholtz-Zentrum Geesthacht the researchers analyzed the locomotory system of a velvet worm.
During a CT analysis, the object under investigation is x-rayed and a detector measures the respective amount of radiation absorbed from various angles....
15.11.2017 | Event News
15.11.2017 | Event News
30.10.2017 | Event News
23.11.2017 | Information Technology
23.11.2017 | Physics and Astronomy
23.11.2017 | Life Sciences